So only in two instances does Paul use the word “sibling” in an unambiguously biological context: Philemon 1:2 and Romans 16:15. Other than that in the vast majority of times (118 times) Paul, Deutero-Paul (Eph, Col, 2 Thes.) and the Pastorals (1 & 2 Tim, [and Titus, but “sibling” isn’t found in that one]), use the word “sibling” to mean a fellow believer.

Above I noted other strange or ambiguous usages of “brother” like in Romans 8:29 where he says that Jesus was the firstborn among brothers. Did Paul mean literal brothers or brothers by faith?

In 1 Cor 6:5; 7:12; 7:14; 7:15 and 9:5 Paul uses “brother” (or “sister”) but the NIV translates it as “believer”. The more obvious interpretation of the NIV translators is at 7:15 where Paul simply says “brother or sister” (ο αδελφος ή η αδελφη:: lit. the brother or the sister) and the translators reveal Paul’s usage of sibling: a believing man or woman.

Later letters by Paul stop using “brothers of the lord” and start using “brothers in the lord” such as Ephesians 6:21, Philipeans 1:14, and possibly Colossians 4:7. But what I think the smoking gun is is at Galatians 6:10 where Paul writes “family of believers”, but actually uses the Greek word for “believers” and not “brothers”. The vast majority of the time Paul is using siblings in the context of the family of believers.

So who knows. Statistically, it’s more likely that Paul meant brother in the context of the family of believers and not an actual blood brother. The two instances of Paul using “brother(s) of the lord” (1 Cor 9:5; Gal 1:19) might be part of the larger context of the family of believers.

2 responses to “Paul’s Use of "Sibling"”

Just curious: on Paul use the word “sibling” in an “unambiguously biological context in Philemon 1:2.” I have never heard that take; never even considered it. Love to hear how you came to that conclusion . You mean that Paul and Timothy are literal brothers with Apphia? Or was the above a typo, and you meant v. 16?